Having been in development for a little while now, FX’s X-Men TV series has found its female lead.

Deadline is reporting that Fargo’s Rachel Keller has signed on to star in Legion, the upcoming X-series. Her exact role is being kept secret for now, although the character is being described as “a scrappy, optimistic woman.” It’s also believed that her mutant powers may centre on physical touch.

Legion will focus on David Haller, a young man who has struggled with mental illness since his teenage years. Classified as schizophrenic and regularly visiting psychiatric hospitals, an encounter with a fellow patient leads him to believe that maybe the voices he hears in his head might actually be more real than some think. Of course, long-time comic book fans will know David as the son of Professor Charles Xavier.

Fargo’s Noah Hawley has penned the show’s pilot and will be serving as executive producer on the series along with Lauren Shuler Donner, Bryan Singer, Simon Kinberg, Jeph Loeb, John Cameron and Jim Chory.

As well as Legion, there’s another X-series in development in the form of Hellfire, although details are still relatively scarce on that project at this stage.